JPS6121982A - Ceramics bonding method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to strongly adhering ceramics to each other, and its purpose is to bond ceramics together by achieving strong adhesive strength and one heat treatment in the atmosphere. The present invention relates to a method characterized by bonding ceramics.

[Background of the invention]

Conventionally, there is no method of directly bonding ceramics to ceramics, but in order to improve the bonding between the brazing material and ceramics, a method of adhering metal to the ceramic surface using a brazing material has been proposed. For example, it is easy to bond ceramics to ceramics, and the purpose can be achieved.

As mentioned above, typical methods for bonding ceramics and metals include (1) Tenfunken method, (2) active metal method, and (8) oxide solder method.

(1) Telefunken method Mix fine powder of Mo, Mo-Mn, or these with additives effective for metallization and an organic binder to form a paste, apply this to the ceramic surface, and apply humidifying hydrogen or humidifying. After metallizing at a temperature of 1,300 to 1,700°C in forming gas and plating Ni on top, Ag-C1 is used as a brazing material.
1 alloy, Ag--Pd alloy, etc. (see Japanese Patent Laid-Open No. 161978/1983).

(2) Oxide solder method Altos -MnO-8in, AttO, -Ca
This is a method in which oxides such as O and Al1011ZrOt are used as a solder, and the solder is placed between the ceramic and the metal and bonded by heat treatment (see JP-A-57-42580).

(8) Active metal method Ti, Zr, etc., which are very active metals, and Ni, Cu, and Ag, which form alloys with relatively low melting points, are interposed between the ceramic and the metal so that they have a eutectic composition. This is a method of bonding by one heating operation in vacuum or inert gas (Japanese Patent Laid-Open No. 56-96784).

The conventional method for bonding ceramics and metals has been described above, but as mentioned above, it is believed that bonding ceramics to ceramics is possible by using this method.

However, it has the following drawbacks.

The disadvantages of the conventional example will be described.

(1) Telefunken method In order to obtain a strong bond, an appropriate composition and appropriate metallization conditions are actually required, and a good bond cannot be obtained unless this process is carried out at a slightly elevated temperature. Regarding brazing filler metal, the most commonly used is BAG-8 (JIS Z
32 & 1) with Ag-Cu eutectic composition (72% Ag remaining Cu
). Depending on the purpose, AU brazing filler metal (J-K5Z3266) may be used. Such conventional methods require the use of a large amount of precious metal, and furthermore, the bonding process is complicated, which is very disadvantageous in terms of cost.

(2) Oxide solder method Oxide solder contains a low melting point solder containing PbO and A
There are high melting point solders whose main components are t, O, and Cao. As a high melting point solder, attempts have been made to use an oxide that forms a eutectic with the composition of the ceramic to be treated.
mp et al. ht, 08-Mn0- by adhesion of alumina to each other
8io! 1100-1400 in hydrogen using eutectic powder
The bonded body is obtained by heating to ℃. However, SiC has a large covalent bond when bonded using the oxide solder method.

It is impossible to bond 81JIN4, etc., and there are disadvantages in that pores are easily formed in the adhesive layer and the adhesive strength is low.

Furthermore, bonding using a high melting point solder method is carried out in a reducing atmosphere such as hydrogen gas, and has the disadvantage that it cannot be bonded by heating in the air.

(8) Activated metal method The bonding method requires one heating operation in vacuum or inert gas.This active metal method has the advantage of completing adhesion with one heating operation and is convenient for use with ceramics. However, it has the disadvantages of using Ag brazing material and requiring vacuum or inert gas. Furthermore, it is necessary to select a combination of the brazing material and the material to be bonded that have matching coefficients of thermal expansion, and there are still considerable problems in selecting the brazing material.

[Purpose of the invention]

In the present invention, Na is added to the bonding surface between ceramics.
, COs powder is applied in the form of a paste with water or an organic solvent, and the adhesive is bonded by one heating operation in the atmosphere.

[Summary of the invention]

The present invention has focused on the drawbacks of the conventional method described above, and has a stronger adhesive force, and can be used in the atmosphere without the need for brazing materials such as Ag or Au, metallization, and atmosphere creation such as vacuum or inert gas. This is a new method of bonding ceramics together using a single heating operation.

In the present invention, a paste made by adding water or an organic solvent to Na and Co3 powder is applied to the ceramic surface, and the adhesive ceramic is placed on top of the paste.
Na and Co are decomposed by the heating operation at ~1200°C to form a gas phase and are firmly bonded. Furthermore, Na2C
Since O3 undergoes crystallization during heat bonding to form a glass phase, it has the advantage that it can be used at a temperature higher than the bonding temperature.

Furthermore, since the glass phase generally has a coefficient of thermal expansion almost equal to that of ceramics, it is possible to obtain a ceramic material with a sound adhesive layer without damage such as cracking during the cooling process after heat bonding.

In the present invention, Na2COs powder, which has been made into a paste by adding water or an organic solvent, is placed on the bonding surface of the ceramic in order to impart caking properties. Next, the most important feature is rapid heating. That is, the adhesion method of the present invention uses Na, c
Through the mediation of Na, 0, which is generated by the decomposition of o,
This is the ht contained in ceramics at the heating temperature of the present invention.
, o3. Sto! , BeQ, etc., exhibits an adhesion effect.

Furthermore, as described above, the bonding of the ceramics of the present invention is carried out by a simple operation of disposing Na, Cos powder on the bonding surfaces of the ceramics and then rapidly heating them in the atmosphere. In this case, when adhering by gentle heating, Na, CO
The decomposition temperature of , is 851°C, but no sodification reaction is observed in this temperature range, and adhesion of ceramics is not achieved. However, by rapidly heating a sample of ceramics with Na, Co, etc. directly inserted into a furnace heated to a temperature of 800°C or higher, the ceramics adhere tightly to the ceramics and have a healthy adhesive layer. A zygote is obtained. This is caused by heating
It is thought that a part of the Na produced by the decomposition of 03 penetrates into the interior of the ceramic composition and exerts a unique adhesion effect. In addition, Na and CO3 decompose and react with the components in the ceramics to form NalCo8-S to, ,
When forming an adhesive layer based on Na2COs -A40m and Na, 0-BeO components, CO is strongly generated, but COt is relatively active against ceramics, so it helps when the adhesive layer penetrates into ceramics. This seems to be the effect. Further, according to the present invention, the heating operation of the adhesive pot only needs to be done once, and post-treatment such as brazing is not required, so it is very economically advantageous.

[Embodiments of the invention]

Example I A paste made by adding a polyvinyl alcohol aqueous solution to Na and CO8 powders was interposed on the joint surfaces of At, O, and SiC plates. Then, it was inserted into a furnace heated to 900°C and bonded for 5 minutes.
An iC/8iC conjugate was obtained.

Example 2 The cross-sectional structure of the Al t Os /A 40m and SiC/SiC bonded body obtained in Example 1 was observed.

Adhesive layer thickness of A l t Os / A l 20 g bonded body: 150 Mm, adhesive layer thickness of SiC/SiC bonded body: 50 Mm, compared to ht, o, /kttos bonded body, SiC/8iC bonded body. The adhesive layer formed in the above was a thinner adhesive layer, and no cracks were observed in either case, indicating that the bonded body had a sound adhesive layer.

Example 3 The sample obtained in Example 1 was heated to 600°C.

A thermal shock test was conducted by heating the sample for 10 minutes and then immersing it in water. As a result, no rotation was observed in any of the samples, indicating that the present invention is a ceramic-to-ceramic bonding method with excellent thermal shock resistance.

Example 4 As a result of examining the adhesive strength of the sample obtained in Example 1, it was A 40 s /A 40 ! The zygote weighs 150kg/
Cm2. SiC/SiC composite is 250 kg/cm
According to the present invention, it is possible to obtain a bonded body of ceramics with high adhesive strength.

〔Effect of the invention〕

1) The present invention uses noble metals such as Ag and Au as brazing filler metals.
Since it is not required, it is very cheap.

2) It is possible to apply a brazing filler metal directly to the ceramic surface and obtain a ceramic-ceramic bonded body without the need for vacuum or inert gas, and moreover, by simply heating in the atmosphere.

Claims (1)

[Claims] 1. Sodium carbonate (N
a_2CO_3) A ceramic bonding method characterized by disposing powder and causing a heating reaction. 2. The ceramic bonding method according to claim 1, wherein the heating reaction is performed by one rapid heating operation in the atmosphere. 3. The method for bonding ceramics according to claim 1, wherein the two ceramic bodies to be bonded are of the same type or type.